Institute of Marine Research, Strandgaten 229, 5004 Bergen, Norway.
Institute of Marine Research, Strandgaten 229, 5004 Bergen, Norway.
Biochim Biophys Acta Mol Cell Biol Lipids. 2018 Sep;1863(9):948-957. doi: 10.1016/j.bbalip.2018.05.006. Epub 2018 May 18.
The zebrafish larva is a powerful tool for the study of dietary triglyceride (TG) digestion and how fatty acids (FA) derived from dietary lipids are absorbed, metabolized and distributed to the body. While fluorescent FA analogues have enabled visualization of FA metabolism, methods for specifically assaying TG digestion are badly needed. Here we present a novel High Performance Liquid Chromatography (HPLC) method that quantitatively differentiates TG and phospholipid (PL) molecules with one or two fluorescent FA analogues. We show how this tool may be used to discriminate between undigested and digested TG or phosphatidylcholine (PC), and also the products of TG or PC that have been digested, absorbed and re-synthesized into new lipid molecules. Using this approach, we explored the dietary requirement of zebrafish larvae for phospholipids. Here we demonstrate that dietary TG is digested and absorbed in the intestinal epithelium, but without dietary PC, TG accumulates and is not transported out of the enterocytes. Consequently, intestinal ER stress increases and the ingested lipid is not available support the energy and metabolic needs of other tissues. In TG diets with PC, TG is readily transported from the intestine and subsequently metabolized.
斑马鱼幼虫是研究膳食三酰甘油（TG）消化以及膳食脂质衍生脂肪酸（FA）如何被吸收、代谢和分布到体内的有力工具。虽然荧光 FA 类似物能够实现 FA 代谢的可视化，但迫切需要专门检测 TG 消化的方法。在这里，我们提出了一种新颖的高效液相色谱（HPLC）方法，可定量区分带有一个或两个荧光 FA 类似物的 TG 和磷脂（PL）分子。我们展示了如何使用该工具来区分未消化和已消化的 TG 或磷脂酰胆碱（PC），以及消化、吸收和重新合成到新脂质分子的 TG 或 PC 的产物。使用这种方法，我们探讨了斑马鱼幼虫对磷脂的饮食需求。在这里，我们证明了膳食 TG 在肠上皮中被消化和吸收，但如果没有膳食 PC，TG 就会积累而不能从肠细胞中转运出去。因此，肠内质网应激增加，摄入的脂质无法满足其他组织的能量和代谢需求。在含有 PC 的 TG 饮食中，TG 很容易从肠道中转运出来，然后被代谢。
